Expansible plate clamp assembly for a cylinder of a printing press



A. COOPER Nov. 28, 1939.

EXPANSIBLE PLATE CLAMP ASSEMBLY FOR A CYLINDER OF A PRINTING PRESS Filed June 22, 1939 jnucnkwp, flrihur (fooper.

Patented Nov. 28, 1939 UNITED STATES PATENT OFFICE Arthur Cooper, Elvaton, Md.

Application June 22,

5 Claims.

This invention relates to printing machines, and especially to an expansible plate clamp assembly of a cylinder of a printing press.

A well known and widely used type of printing cylinder is formed with peripheral grooves in which are removably secured quadrants or segments of the special shape here shown in part, each quadrant having at least one pair of parallel tracks, guides or gibs that are also parallel to the axis of curvature of the quadrants or segments. Between and slidingly engaged with the gibs is a two-piece plate-engaging device that consists of an apertured internally screw-threaded jaw-unit, and an adjusting screw therethrough for advancing the jaw-unit and tightening it against the adjacent edge of the respective printing plates. Because of the heavy, rough, rapid and oft-repeated usage of such devices, very considerable wear and distortion develops on the gibs and in the grooves where the respective jawunits are slid along the gibs, and this causes an excess looseness and consequent tilting of, the jaw-unit, resulting in the breaking of the contiguous edge of the printing plate, so the latter is rendered inaccurate, menacing, and useless in many cases. Because of the intricate form of the quadrants, or segments, the cost of replacing them with new ones amounts to over for each segment to be replaced.

One object of the present invention is to provide an improved form; or type of plate-clamping element or jaw that obviates or precludes the dis:- advantages referred to in the foregoing, and thereby to save money, time and worry as to the users of printing rollers or cylinders of the type described.

A further objectv is to provide a plate-edgeengaging member that is automatically expanded by the same operation that tightens it against the edge of the plate it is to assist in holding on the printing cylinder.

Other objects and important features are pointed out or implied in the following details of description, in connection with the accompanying drawing in which:

Fig.- 1 is a top plan view of a fragment of a quadrant of the kind referred to in the foregoing, and of one of my expansible plate-clampjaws seated between the gibs of the quadrant.

Fig. 2 is a front edge view of the same mechanism as shown in Fig. 1.

Fig. 3 is a top plan view of the left-side element of the expansible jaw.

Fig. 4 is a top plan view of the apertured in- 1939, Serial No. 280,496

ternally screw-threaded wedge or intermediate element of the expansible jaw.

Fig. 5 is a top plan View of the right-side element of. the expansible jaw.

Fig. 6 is a sectional view along the line 6-6 of Fig. 3.

Fig. '7 is a horizontal sectional view of the same element shown in Fig. 5, showing that the lower wedge-guiding flange is substantially the same shape as the upper one'of these two flanges.

Referring to the drawing in detail, in which, similar reference numerals refer to similar parts in the several views, the invention is described in detail as follows: Two complemental wedge-seatblocks 8 and 9 are slidingly engaged "with one another by means of pairs of inter-lapping projections or tongues 8a, 812 and 9a, or by a dowel 9b and socket 80, or by both means here shown, viz., the interlapping tongues and interengaged dowel and socket, so they can be moved freely towards and from one another, but cannot move laterally with respect to one another. Each up per tongue 8a and 82) has its counterpart lower tongue (not shown), and each upper tongue 9a has its counterpart lower tongue 9a, as shown in Fig. 7, to be interlapped with the lower tongues of the wedge-seat-block 8, according to the present disclosure of the invention; but it is quite within the scope of this invention to eliminate either the upper or thelower interlapped tongues. However, the tongues, as here shown and described, are portions of upper horizontal flanges 8d and 9d and lower flanges 8e and 9e; and while, incidentally, the upper flanges are shown as united with overhanging walls or plate-grip-elements, such plate-grip-elements do not necessarily extend over the flanges, inasmuch as their main parts are elements that donot extend to these flanges and are eiiective without the parts that extend over the flanges.

The block 8 has at its inboard side an upright surface 89/ whose upper and lower edges adjoin the upper and lower flanges 8d and 8e respectively and combine therewith to form a wedge-seat, the surface 8gbeing inclined to the opposite or outboard sideof the block which includes a gib-engaging groove 8h.

The block 9 has at its inboard side an upright surface 99 whose upper and lower edges adjoin the upper and lower flanges 9d and 9e respectively and combine therewith to form a wedge-seat, the surface By being inclined to the opposite or outboard side of the block, which opposite side includes a gib-engaging groove 9h.

A wedge ID has an internally screw-threaded 55 bore lUa, throughout its length, and is preferably formed with one or more retaining lugs 10b which have an additional function presently to be shown. A screw l i normally extends through the threaded bore or aperture IM and is interengaged with the threads thereof, and this screw is preferably formed with a spur-gear Ma and with a reduced pivotal extension I lb.

When in use, the blocks 8 and 9 are interengaged with one another and with the wedge ID in the manner shown in Figs. 1 and 2, and their gib-engaging grooves are slidably engaged with gibs [2 while the pivot lib is journaled in a socket 520, of a segmental securing element lZb that is united with the gibs so as to hold them rigidly in a fixed parallel relation to one another, a screw-hole I20 being provided in this element for receiving a screw for fastening this segmental element to a cylinder which includes spaced walls 13 and it.

The operation is as follows:

Assuming that one edge of a printing plate is beveled and seated against the knurled under side of the overhanging plate-grip-elements of the blocks 3 and 9 while the opposite edge of the plate is seated against a similar pair of plategrip-elements, and that the screw H is turned in the proper direction for cooperating with the element 12b in pushing the assembly 8-9-l0 in the direction towards the wall it; this same operation, that causes the assembly to advance, also causes the wedge to slide on the inclined surfaces 8g and 99' and thereby force the blocks to move in opposite directions, viz., laterally of the gib-engaging grooves, or away from the axis of the screw and very tightly press against the gibs 12 so as to preclude any tilting movement of the blocks or of their plate-grip-elements, thus avoiding the disadvantages and dangers mentioned in the foregoing.

When it is desired to unclamp the printing plate, the screw II is turned in the proper direction for pressing its ends against the wall l4 and cooperating with the latter for retracting the wedge; and if the blocks 8 and 9 do not immediately retract from the printing plates edge, the lugs lllb will press against the blocks to cause them to retract from the plates edge.

By thus precluding lost motion between the clamp assembly and the gibs l2, wearing and battering of the latter is reduced to the minimum, and when finally it may become necessary to dress the gibs for making them true and parallel, the same assembly can be used, the wedge having sufiicient slope and scope to compensate for the widening of the space between the gibs.

Though I have described this embodiment of my invention specifically I have no intention to limit my invention to the precise details of construction and arrangement here shown and described; and while it is preferable to form all parts of the invention from steel, it is quite within the scope of this invention to form them of metal or material other than steel. The invention is limited only by the inventive ideas as implied and expressed in the claims.

What I claim as my invention is:

1. A plate clamp assembly comprising two interengaged blocks each having a plate-grip-element on its upper side and each having an upright side formed with a groove for sliding engagement with one of two parallel gibs, and means operable to move said blocks in the same direction for causing them to slide along said gibs and thereby to press their plate-grip-elements against a plates edge and to move'them in opposite directions laterally of the gib-engaging grooves for pressing them tightly against the respective gibs, substantially as described.

2. A plate clamp assembly comprising two blocks which have elements normally interengaged in the proper relation to prevent these blocks from moving laterally with respect to one another and to permit them to be moved in opposite directions, each of said blocks having a plate-grip-element thereon and having a groove disposed horizontally in its outboard upright side for sliding engagement with one of two parallel gibs, a wedge slidably seated between said blocks, and means to slide said wedge in the proper relation to'move the blocks in the same direction along said gibs and to move the blocks in opposite directions laterally of the gib-engaging grooves for seating them tightly against said gibs.

3. The combination defined by claim 2, said wedge having an internally screw-threaded aperture therein, and said means being inclusive of a screw engaged with the thread of said screwthreaded aperture and adapted to abut against an object for causing said wedge to move with respect to said blocks. a

4. The combination with two spaced parallel gibs and an adjacent abutment, of a plate clamp assembly comprising two blocks each having an inboard side formed with a wedge-seat, each block having an outboard side'formed with a groove which is slidingly engaged with one of said gibs, each block having a plate-grip-element that extends transversely of the space between the gibs, a wedge slidably seated against said wedge-seat and having an internally screwthreaded aperture therein, and a screw engaged withthe thread of said screw-threaded aperture of the wedge and being operable against said abutment for moving said wedge in the proper relation for moving said blocks in the same direction transversely of the plate-grip-element and for moving said blocks in opposite directions laterally of the gib-engaging grooves for pressing them tightly against said gibs, for purposes specified.

5. The combination defined by claim 4, and a second abutment, said screw extending entirely through said wedge and having one end substantially against one of said abutments while the other end is substantially against the other one of said abutments, for purposes specified.

ARTHUR COOPER. 

